LOGIC SYMBOLS

Question 1

v

Answer 1

V = disjunction, "or..."
V = T iff at least one disjunct is true

Question 2

∧

Answer 2

∧ = conjunction, "and..."
∧ = T iff both conjuncts are true

Question 3

→

Answer 3

→ = conditional, "if...then..."
→ = T iff the antecedent is false or the consequent is true

Question 4

↔

Answer 4

↔ = biconditional, "if and only if...", "iff"
↔ = T iff both sides left and right have the same truth value. so either both true or both false.

Question 5

¬

Answer 5

¬ = negation, “it is not the case that…”, “not…”
¬ = reverses the truth value of whatever formula it is placed in front of/applied to
eg, say (P∧Q) = T, then ¬(P∧Q) = F

Question 6

T

Answer 6

T = “true”

Question 7

F

Answer 7

F = “false”

Question 8

⊨

Answer 8

⊨ = a tautology , “it is unconditionally/always true that…”
eg, if ⊨ P or ⊨ Q then ⊨ ¬ P → Q

Question 9

≔

Answer 9

≔ = definition, “is defined as…”

x ≔ y means that x is defined as y, another name for x is y